Modular drum generator

Abstract

The present invention is an improved modular drum generator which plays a recorded drum beat and which may be used in combination with a plurality of identical, improved modular drum generators to provide an electronic percussion section. The improved modular drum generator includes a bistable latch which has a clock input, which is electrically coupled to a computer which generates a "play" strobe pulse, a set of three data inputs, one of which is held at logic "1" and the other two of which are electrically coupled to a computer data bus which also generates volume data and pitch data, a reset input and a set of three outputs corresponding to the data inputs. The improved modular drum generator further includes a voltage controlled oscillator the input of which is electrically coupled to the pitch output of the bistable latch and the output of which is electrically coupled to the clock input of a twelve bit binary counter, which provides 2 12 data words, thereby controlling the frequency of data conversion thereof. The enable count input of the twelve bit counter is electrically coupled to the "play" output of the bistable latch and the end of count output is electrically coupled to the reset input of the bistable latch. The improved modular drum generator further includes a read only memory, which contains 2 12 binary words representing same on an analog waveform, which is a recording of the sound of a single drum strike, a digital to analog converter, which is electrically coupled to the read only memory in order to receive the binary words and to reconvert it to analog data so that it can be played through an amplifier, and an amplifier, which is electrically coupled to the analog to digital converter.

What is claimed is: 
     
       1. An improved modular drum generator, which plays a prerecorded drum tone in response to a "play" strobe signal, comprising: a. a bistable latch having a first data input which is electrically coupled to a logic "1", a first data output, a clock input which receives the "play" strobe signal and a reset input;   b. a voltage control oscillator having a control voltage input which is electrically coupled to a variable voltage source and an oscillating output;   c. a binary counter having an enable count which is electrically coupled to the first output of said bistable latch, an end of count which is electrically coupled to the reset input of said bistable latch, a clock input which is electrically coupled to the oscillating output of said voltage control oscillator and an output;   
     
     
       d. a read only memory which contains a digitized word which represents a single drum beat and which is electrically coupled to the output of said binary counter; e. a digital to analog converter which is electrically coupled to said read only memory in order to receive the digitized word so that said digital to analog converter can reconvert the digitized word back to analog data;   f. an analog switch having a digital input which is electrically coupled to the second output of the said bistable latch, said analog switch electrically couples a first resistor to a second resistor in parallel only when said analog switch is "on"; and   g. an amplifier having an input which is electrically coupled to said digital to analog converter through said first resistor when said analog switch is "off" and to said first resistor and said second resistor in parallel when said analog switch is "on" whereby the volume of the drum beat be adjusted between two levels by said analog switch.   
     
     
       2. An improved modular drum tone generator according to claim 1 wherein said bistable latch further has a third data input which receives a pitch data signal and a third data output and wherein said improved modular drum tone generator further comprises: a. a third resistor which is electrically coupled to the input of said voltage control oscillator and to the third data output of said bistable latch in order to increase and decrease the voltage whereby the pitch of the drum beat may be adjusted between two frequency levels.